Failure in Confined Brazilian Tests on Sandstone

Strength of rocks in the confined tension region, where minimum principal stress is tensile, has only infrequently been measured and not well understood. Quasi-static Brazilian tests under a range confining stresses (2.76 to 27.58 MPa) used determine strength sandstone region. The test results indicate that region was strong function intermediate stress: increasing significantly increased sandstone. data were fit by Mogi–Coulomb criterion, which accounts for stress. Unconfined criterion derived from data, consistent with transition tensile shear processes dominating failure pressure. Observations post-failure fracture surfaces reveal more indication Numerical simulations combined finite-discrete element method are compared experimental reflect similar conditions